//@ts-check
const { Lexer } = require('../lib/sheebr/lexer')
const { getline } = require('../lib/sheebr/utils')
const fs = require('fs')
let environment = require('../lib/sheebr/environment')
let aliases = require("../lib/sheebr/aliases")
let execSync = require('child_process').execSync


let current_dir = process.cwd()

start()

async function start(){
    while(true){
        const input = await getline("sheebr> ");
        if(input == "exit") break;
        if(input == "") continue;
        else evaluate(input);
    }
}

function evaluate(input){
    let lexer = new Lexer(input)
    let args = lexer.scanTokens()
    args = evaluateAliases(args)
    args = evaluateEnvironmentVariables(args);
    switch(args[0]){
        case "cd":
            if(args.length != 2){
                console.log("Wrong number of arguments"); return;}
            if(!fs.existsSync(args[1])){console.log("Folder does not exist"); return;}
            current_dir = args[1][0] == "/" ? args[1] : current_dir + '/' + args[1];
            //console.log(current_dir)
            break;
        case "set":
            environment[args[1]] = args[2];
            break;
        case "alias":
            if(args.length == 1) console.log(aliases);
            else if(args.length == 2){
                console.error("Wrong number of argument")
            }
            else{
                aliases[args[1]] = args[2].split(" ")
            }
            break;
        case "clear":
            console.clear();
            break;
        default:
            evaluateProgram(args)
    }

}



function evaluateProgram(args){

    let found = false;
    for(let path of environment.path){
        let tobreak = false;
        const files = fs.readdirSync(path);
        if(files.includes(`${args[0]}.js`)){
            found = true;
            //@ts-expect-error
            const script = execSync(`${environment.node} ${path + '/' + args[0]}.js ${args.map(arg => {return arg.includes(' ') ? `"${arg}"` : arg}).join(' ')}`, {cwd: current_dir, env: environment, shell: true});
            process.stdout.write(script)
            tobreak = true;
        }

        if(tobreak) break;
    }
    if(!found){
        console.log("Program not found")
    }
}

function evaluateEnvironmentVariables(args){
    let newArgs = []
    for(let arg of args){
        if(arg.startsWith('$')){
            if (arg.slice(1) in environment)
                newArgs.push(JSON.stringify(environment[arg.slice(1)]));
            else
                console.error(`variable ${arg.slice(1)} does not exist.`);
        }
        else{
            newArgs.push(arg)
        }
    }
    return newArgs;
}

function evaluateAliases(args){
    if(args[0] in aliases){
        return aliases[args[0]].concat(args.slice(1))
    }
    return args;
}